JP2004146967A - Structure of piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for a piezoelectric oscillator which has a smaller planar area and does not need a substrate electrode pad to be connected by soldering with a lead terminal from a mold base. <P>SOLUTION: Surface mount electrode parts 18 on the bottom face of the mold base 15 are extended and folded in an L shape along a sidewall of the mold base 15 to obtain connection electrode parts 19 which are projected above the sidewall upper face of the mold base 15. Electrode films 17 formed on a cut end face of a notched part 16 at four corners of a printed wiring board 13 are soldered and integrated with the connection electrode parts 19. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a crystal oscillator, and more particularly, to a structure of a miniaturized crystal oscillator used for a portable wireless terminal or the like.
[0002]
[Prior art]
2. Description of the Related Art In recent years, wireless communication devices, particularly portable wireless terminals, have been improved in function and reduced in size and weight, and there has been an extremely strong demand for smaller components.
4A and 4B are external views showing an example of the structure of a conventional crystal oscillator used for a portable radio terminal or the like disclosed in Japanese Patent Application Laid-Open No. 2000-36716, wherein FIG. 4A is a perspective view, and FIG. (C) is a longitudinal sectional view, and (d) is a bottom view.
As shown in the figure, a crystal oscillator 51 and an oscillation circuit component 52 are mounted on the upper surface of the crystal oscillator 50, and another oscillation circuit component 53 is mounted on the lower surface. The printed wiring board 55 provided with the provided substrate electrode pads 54 is provided with an electrode plate 56 having concave portions on the upper side and serving as input / output terminals of the crystal oscillator 50 at four lower corners, and connected to the electrode plate 56 to The lead terminal 57 is fitted on a through-hole of the substrate electrode pad 54 by placing the lead terminal 57 on a mold base 58 formed by molding a resin or the like having lead terminals 57 penetrating through the concave portion side wall and projecting at four corners of the upper surface of the side wall. Then, the structure is integrated by soldering 59.
When the present crystal oscillator 50 is used in an apparatus or the like, the electrode plate 56 on the lower surface of the mold base 58 is soldered to a circuit pattern or the like of a printed wiring board of a portable wireless terminal or the like. The oscillation output of the crystal oscillator 50 is taken out from the electrode plate 56 via the substrate electrode pad 54 and the lead terminal 57, and the power to the crystal oscillator 50 is supplied through the reverse path.
[0003]
[Problems to be solved by the invention]
However, as described above, the board electrode pads 54 provided at the four corners of the upper surface of the printed wiring board 55 are connected to the lead terminals 57 of the mold base 58 by soldering, and are in contact with components mounted on the upper face of the board. In order to avoid this, a predetermined space is required. For example, the area of the upper surface of the printed wiring board 55 is, for example, a major obstacle to miniaturization of the crystal oscillator of about 5.0 × 3.5 (mm).
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a crystal oscillator having a further miniaturized structure.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 includes a base member having a concave portion on an upper surface and an electrode plate on a lower surface, and a printed wiring board on which components constituting an oscillation circuit are mounted on both surfaces. Wherein the electrode plate of the base member extends from the lower surface of the base member along the outer surface of the side wall of the base member, and has a substantially L-shaped tip protruding from the upper surface of the side wall of the base member. An electrode film is formed at a position corresponding to the electrode plate on the substrate end surface of the printed wiring board, and the electrode film and the electrode film of the printed wiring board placed on the upper surface of the base member side wall are conductively fixed. Characteristic structure of piezoelectric oscillator.
According to a second aspect of the present invention, in the structure of the piezoelectric oscillator according to the first aspect, the electrode film of the printed wiring board is formed in a cut cross section of a cutout provided at an end of the board. It is characterized by.
According to a third aspect of the present invention, in the structure of the piezoelectric oscillator according to the first or second aspect, the notch has an arc shape.
According to a fourth aspect of the present invention, in the piezoelectric oscillator structure according to the first or second aspect, the printed wiring board has a substantially rectangular planar shape, and the electrode film is formed near a vertex thereof. It is characterized by the following.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on an embodiment shown in the drawings. 1A and 1B are external views showing an embodiment of the structure of a crystal oscillator according to the present invention, wherein FIG. 1A is a perspective view, FIG. 1B is a top view, FIG. 1C is a side view, and FIG. FIG.
As shown in FIG. 1A, the crystal oscillator 10 comprises a crystal oscillator 11 and an oscillation circuit component 12 mounted on an upper surface and another oscillation circuit component (not shown) mounted on a lower surface to form a crystal oscillation circuit. It comprises a printed wiring board 13 and a mold base 15 formed of a resin or the like having recesses on the upper surface and embedding external electrode plates 14 at four corners on the lower surface as described below.
Then, as shown in FIGS. 4B, 4C and 4D, cutouts 16 are provided at the four corners of the printed wiring board 13, and the cut end faces of the cutouts are formed by plating. And an electrode film 17 connected to an oscillation output circuit or a power supply circuit.
Further, the external electrode plate 14 embedded in the mold base 15 has a surface mounting electrode portion 18 provided on the lower surface of the concave portion, and the surface mounting electrode portion 18 is enlarged and extended along the concave portion side wall. It is bent upward in an L-shape, and its upper end is composed of a connection electrode portion 19 with the printed wiring board 13 protruding from the upper surface of the side wall of the recess.
[0006]
When the printed wiring board 13 is placed on the upper surface of the side wall of the mold base 15 having the above structure, the connection electrode portion 19 on the upper surface of the side wall of the mold base 15 is fitted with the notch 16 of the printed wiring board 13. . Then, the mold base 15 and the printed wiring board 13 are integrated by soldering the connection electrode portion 19 and the electrode film 17 on the cut end face of the cutout portion 16.
When the crystal oscillator 10 is used in a device such as a portable wireless terminal, the surface mounting electrode portion 18 on the lower surface of the mold base 15 is soldered to a circuit pattern or the like of a printed wiring board of the portable wireless terminal or the like. The oscillation output of the crystal oscillator 10 is extracted from the surface mounting electrode portion 18 through the electrode film 17 of the cutout 16 and the connection electrode portion 19, and the power supply to the crystal oscillator 10 is reversed. Is supplied by the route.
With the above structure, the present crystal oscillator 10 does not require a substrate electrode pad on a printed wiring board as in the related art, so that the substrate area can be significantly reduced.
[0007]
2A and 2B are external views showing a modified example of the structure of the crystal oscillator according to the present invention, wherein FIG. 2A is a perspective view, FIG. 2B is a top view, FIG. 2C is a side view, and FIG. is there.
As shown in FIG. 1A, a crystal oscillator 30 includes a printed circuit board 34 having a crystal oscillator 31 and an oscillation circuit component 32 mounted on an upper surface, another oscillation circuit component 33 mounted on a lower surface, and a concave portion formed on an upper surface. And a mold base 38 formed of a resin or the like in which external electrode plates 37 described later are embedded in the four corners of the lower surface.
As shown in FIGS. 8B, 8C, and 8D, a notch 35 is provided near a vertex of a long side of the printed wiring board 34 having a substantially rectangular planar shape. The cutout portion 35 is formed by cutting the printed wiring board 34 in an arc shape, and the cut end surface of the cutout is formed by plating, and an electrode film 36 connected to an output circuit of an oscillation circuit or a power supply circuit or the like. Is provided.
The external electrode plates 37 embedded in the four corners of the mold base 38 are provided with a surface mounting electrode portion 39 provided on the lower surface of the concave portion, and a part of the surface mounting electrode portion 39 is enlarged and extended along the concave portion side wall. It is bent upward in an L-shape, and its upper end is formed of a connection electrode portion 40 for connection with a printed wiring board protruding from the upper surface of the side wall of the recess.
[0008]
When the printed wiring board 34 is placed on the upper surface of the recessed side wall of the mold base 38 having the above structure, the connection electrode portion 40 of the mold base 38 and the cutout 35 of the printed wiring board 34 are fitted. . Thereafter, the mold base 38 and the printed wiring board 34 are integrated by soldering the connection electrode portion 40 and the electrode film 36.
When the connection electrode portion 40 of the mold base 38 is fitted with the notch 35 of the printed wiring board 34, the tip of the connection electrode portion 40 protrudes from the upper surface of the printed wiring board 34. (Or even 0.1 mm or less even if it protrudes), and the shape of the tip of the connection electrode portion 40 is a fitting and assembling operation between the notch 35 of the printed wiring board 34 and the mold base 38. Is chamfered so that it can be performed smoothly.
With the above structure, the upper surface of the printed wiring board can be used more efficiently, so that a small crystal oscillator having an extremely small plane area can be configured.
[0009]
3A and 3B are external views showing a modified example of the mold base of the crystal oscillator shown in FIG. 2, wherein FIG. 3A is a plan view and FIG. 3B is a side view. As shown in the figure, the main mold base 41 includes an external electrode plate 37 having the same structure as that of FIG. 2, a hole 42 having a size described later provided on the bottom surface, and a main mold base 41 having a substantially rectangular planar shape. The upper surface provided at two suitable long edges and the other one edge of the four sides is flat, and the protrusions 43 having the same height from the lower surface of the mold base 41 and the surface of the external electrode plate 37 are provided. A concave portion 44 is formed on the inner bottom surface of the mold base 38 corresponding to the mounting electrode portion 39.
[0010]
As described above, the mold base 41 is provided with the hole 42 at the bottom (indicated by oblique lines in the figure) of the oscillation circuit component mounted on the lower surface of the printed wiring board mounted on the upper surface. ing. Therefore, when the printed wiring board is placed on the main mold base 41, the height of the main mold base should be reduced to a range where the lowermost end of the oscillation circuit component mounted on the lower surface of the printed wiring board does not protrude from the lower surface of the main mold base 41. And the height of the crystal oscillator can be further reduced.
[0011]
The external dimensions of the crystal oscillator shown in FIG. 2 are small, for example, about 5.0 × 3.5 × 1.5 (mm), and the height of the mold base 41 not including the external electrode plate 37 is small. For example, since the molded product is made of a very thin resin having a thickness of, for example, about 0.5 mm, the molded product may have a warp during molding.
When a printed circuit board is mounted on a side wall surface having a flat top surface, the mold base may be loose and the mold base may be damaged.
On the other hand, when the printed wiring board is placed on the protrusions 42 provided at the three edges of the mold base 41 of FIG. 3, the surface formed by connecting the three points is flat. Of the mold base can be eliminated, and damage to the mold base can be prevented.
The concave portions 44 at the four corners of the inner bottom surface of the mold base 41 are used for soldering the electrode portions 40 for connection of the external electrode plate 37 of the mold base 41 and the electrode films 36 on the end surfaces of the cutout portions 35 of the printed wiring board. This prevents the solder from flowing around the external electrode plate and causing an obstacle to an adjacent component or circuit pattern.
[0012]
【The invention's effect】
As described above, according to the structure of the crystal oscillator of the present invention, the external electrode plate on the bottom surface of the mold base is extended and bent in an L shape along the mold base side wall, and the upper end protruding from the upper surface of the mold base side wall And the electrode film formed on the cut end face of the cutout at the four corners of the printed wiring board are integrated by soldering, so that the printed wiring board is connected to the lead terminals from the mold base as before. This eliminates the need for substrate electrode pads for soldering connection, and makes it possible to reduce the plane area of the crystal oscillator.
In addition, a hole is made in the bottom of the mold base at the part facing the component mounted on the lower surface of the printed wiring board. Can be lowered. Therefore, the height of the crystal oscillator can be further reduced.
As described above, the present invention can greatly contribute to providing a very small crystal oscillator.
[Brief description of the drawings]
1A and 1B are external views showing an embodiment of the structure of a crystal oscillator according to the present invention, wherein FIG. 1A is a perspective view, FIG. 1B is a top view, FIG. 1C is a side view, and FIG. Is a bottom view.
2A and 2B are external views showing a modified example of the structure of the crystal oscillator according to the present invention, wherein FIG. 2A is a perspective view, FIG. 2B is a top view, FIG.
3A and 3B are a top view and a side view showing an outer shape of a mold base of the crystal oscillator shown in FIG.
4A and 4B are external views showing an example of the structure of a conventional crystal oscillator, wherein FIG. 4A is a perspective view, FIG. 4B is a top view, FIG. 4C is a side sectional view, and FIG.
[Explanation of symbols]
10. Crystal oscillator, 11 Crystal oscillator, 12 Oscillator circuit parts,
13. Printed circuit board, 14. External electrode plate, 15. Mold base,
16 ··· Notch, 17 ··· Electrode film, 18 ··· Surface mounting electrode part,
19 ・ ・ Electrode part for connection with printed wiring board
30, crystal oscillator, 31, crystal oscillator, 32, 33, oscillation circuit parts,
34 .. Printed wiring board, 35. Notch, 36 .. Electrode film,
37 · · · external electrode plate, 38 · · · mold base,
39..Electrode part for surface mounting, 40..Electrode part for connection with printed wiring board,
41 ... mold base, 42 ... hole, 43 ... protrusion,
44 ...
50 crystal oscillator, 51 crystal oscillator, 52 oscillation circuit parts
53 ... oscillation circuit parts, 54 ... board electrode pads, 55 ... printed wiring board,
56 .. electrode plate, 57 .. lead terminal, 58 .. mold base,
59 ・ ・ Soldering

Claims (4)

A piezoelectric oscillator comprising a base member having a concave portion on the upper surface and having an electrode plate on the lower surface, and a printed wiring board mounted with components constituting an oscillation circuit on both surfaces,
The electrode plate of the base member extends from the lower surface of the base member along the outer surface of the side wall of the base member, and has a substantially L-shaped tip protruding from the upper surface of the side wall of the base member. An electrode film is formed at a position corresponding to the electrode plate, and the electrode film and the electrode plate of the printed wiring board mounted on the upper surface of the side wall of the base member are conductively fixed. . The piezoelectric oscillator structure according to claim 1, wherein the electrode film of the printed wiring board is formed in a cut cross section of a notch provided at an end of the board. The structure of the piezoelectric oscillator according to claim 1, wherein the shape of the notch is an arc. 3. The piezoelectric oscillator according to claim 1, wherein the printed wiring board has a substantially rectangular planar shape, and the electrode film is formed near a vertex of the printed wiring board.

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